Chronograph mechanisms generally comprise a chronograph counter train which can count the time from the second, by means of a chronograph wheel set or seconds-counter, to the minute, by means of a minute-counter, and possibly to the hour, by means of an hour-counter. Each counter comprises an indicator member moving on a corresponding graduated scale. When the chronograph is reset to zero, the indicator members are conventionally indexed to an angular position corresponding to the zero on each graduated scale. Therefore, the indicator members are generally carried by the arbor of a corresponding gear train element, and there is a friction connection between the gear train element and its arbor to allow for an independent angular motion of the two members beyond a certain torque. The indicator members are indexed by means heart-piece mechanisms and corresponding hammers. The use of friction connections and heart-piece mechanisms and hammers means that the torque to be provided when the various counters are reset to zero is very high, and that a large quantity of energy will be consumed simply to reset the various counters to zero. Accordingly, the manufacturer is obliged to provide a suitable energy accumulator, generally a barrel of sufficient size to provide the required energy. This creates a congestion problem, in particular in the case of a timepiece comprising a basic time movement and an autonomous chronograph movement, having its own movement and therefore its own barrel. It is therefore necessary to have mechanisms that use less energy when the chronograph is reset to zero. More specifically, it is necessary to have a chronograph zero-reset mechanism other than a friction system controlled by heart-pieces and hammers.